Method of manufacturing tub staves



3 Sheets-Sheet 1 @www PaulL. Bl um P. L. BLUM May 29, 1956 METHOD OFMANUFACTURING TUB STAVES Original Filed May 9, 1950 May 29, 1956 P. l..BLUM 2,747,629

METHOD OF MANUFACTURING TUB STAVES Original Filed May 9, 1950 3Sheets-Sheet 2 Flag a.

May 29, 1956 P. l.. BLUM 2,747,529

METHOD OF' MANUFACTURING TUB STAVES f I w M f z Wel '/2 Fai-,10

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29 28 Paul L. Blum akkoznuj United States Patent O METHOD oFMANUFACTURING rua srAvEs Paul L. Blum, Marshfield, Wis., assigner toBlum Bros.

Box Company, Marshfield, Wis., a corporation of Wisconsul Originallapplication May 9, 1956, Serial No. 16},9l4, now Patent No. 2,673,585,dated March 30, 1954. Divided and this application February 10, 1954,Serial No. 409,378

Claims. (Cl. 144-309) This invention is directed to the art of makingWooden receptacles and pertains particularly to improvements in themanufacture of tubs of tapered form such as are conrmonly employed inthe marketing of butter, lard and other commodities.

A particular object of the present invention is to provideran improvedmethod of producing staves of the correct taper, edge bevel andtransverse curvature in an eicient manner and with greater economy thanby the presently practiced methods, together with means for carryihg outsuch method.

In the manufacture of staves for butter tubs and smilar receptacles, asat present practiced, the method employed embodies a predeterminedprocedure of cutting the timber to produce incomplete stave pieces ofvarcuate crossY sectional form and having unbeveled parallellongitudinal edges. After the formation of the piece'in this manner,each piece is sawed to the desired taper and bevel, the result being theremoval from each side of thepiece of a sliver having a thickness at oneend of about one-half inch, which is discarded. Thus from each stavepiece there is removed waste material of the length of the piece havinga thickness of about one-half inch and. a width equal to the thicknessof the stave piece. Where in a large tub producing factory the number ofstaves used in aV year runs into the hundreds of thousands and probablymillions, the waste material from the forma- -tion ofthe. staves inthemanner stated is considerable.V

A further object of the present invention is to provide an improvedmethod of manufacturing the tub staves whereby the sequence' ofoperations is changed from that at present; employed so that the stavesare initially formed withaproper taper and bevel and the removal ofwaste material from thev sides of the pieces is avoided, as a result ofwhich material previously cut oli and thrown away as waste now goes intothe completed stave and Wastageis reduced to a minimum.

Another object of the'invention is to providey a novel methodA ofmanufacturing staves for taperedY butter` tubs and similar receptaclesfrom material whichat the present time constitutes' wastage from doorand window frame andf'sash'rmills, wherein such Wastage compriseslpieces offwood' stock of fromV fifteen and' one-half to sixteen andone-half inchesV in length and varying in thickness from one inch= to'.onev and live thirty secondsV inchesrandA in width varying fromrtwo andone-half inches to tive inches or more, by a novel processof joiningsuchpieces into a preliminary blank andthen taper sawing such blank' on amachine ofnovel construction to produce an initial properly beveledfandtapered piece from which two iinished stavesare produced.

Other objects and advantages of the invention will become apparent asthe description of the same proceeds and the invention will' be bestunderstood from a consideration' of the following` detailed descriptiontaken inconnection: with the accompanyingV drawings forming a part ofthespecification, withA the understanding, however,.th'at the invention is:not: to`Y be limited tolthe exact detail'sfcf construction shown anddescribed since obvious modications will occur to a person skilled inthe art.

ln the drawings:

Figure l is a ow chart showing the different operating stations incarrying out the herein described method in the progress ofthe materialfrom the stage in which it is received to the completed stave.

Figure 2 is a plan view of the blank as made up from the differentpieces of material and showing how the first trim piece is produced inthe making of the initial cut of the blank. y

Figure 3 is an edge view of the blank asillustrated in Figure 2.

Figure 4vr is a'view illustrating the manner of making the rst cut ofthe blank according to' one procedure;

Figure 5 is a view illustrating the manner of making the second cut' ofthe blank according 'to the alternative procedure which may be'followed.

Figure 6v is a view in plan ofthe blank asrec'eived at the formermachinerwith' a previouslyproduced' trim strip forming a part thereof,the blank further being lined to indicate'the cuts for producing thestave pieces.

Figure 7 is an end edge view of the blank' asv shown in Figure 6;

Figure 8 is a view in perspective, looking at the inside face, of astave piece from which two incompleteV staves are formed' andsliowing'the'arcuate'line of cut a'sfollowed by the cutting saw.

Figure 9 is a view looking at the'sma'ller endl'of the stave.` pieceshown inI Figure 8` and illustrating the angle of the beveledlongitudinal edges thereof.

FigurelO- shows in an end View, the topl incomplete stavepiecesas'produced from the blank shownv in Figure' 8.

Figure 11 is a View illustrating conventionally convex and` concaveplaners by which the at faces of the incomplete stave pieces are planedto a transverse arcuate contour.

Figure 12 is a view illustrating the manner'of making the rst cut of ablank according to one formi of procedure where the blank includes inits make-up the trim' strip resulting from the first cutting of theblank formed as illustrated in Figure 2.

As hereinbefore set forth iny practicing thefpre'sent invention use ismade of waste piecesV of the materialsuch as. may be obtained' from any'one of numerous Window and door framew or sash manufacturing mills,such4 Waste pieces, which are of Ponderosav pine, customarily runningfrom fteen and one-half to sixteen and one-half inches in length andhaving' a widthv of from twoand' one-half inches to tive inches or moreand a thickness of from one inch to one and five thirty seconds inches.

It will, of course, be'understoodv that the-present method is notrestricted to the-use of the waste'pieces of this particular type sincelonger pieces of material may be .employed by reducing them to theproper lengthsbut the present method is of particulareconomicirnportance to the art in the fact that the usual sourcesof'available long length material are decreasing due to=the depletion offorests of the correct type of wood and the present method wasaccordingly devisedy with a view to u'singithe material which heretoforehad been useless and at the same time reducing the wastage of suchmaterialV to a minimum.

In carrying out the method, where itis necessary the pieces of materialare reduced to the proper thickness and the pieces are then run througha cut-ott saw machine, diagrammatically' shown and designated 10 in thechart, where such pieces aregiven the proper length for the particularsize tub to be constructed from the iinishedstaves.

Standard size butter tubs holding' sixty ve pounds of butter measureabout V fourteen and' seven-eighths inches .iada'meter insideof the' topand' about' twelve inches ina I 3 side diameter at the bottom andapproximately thirteen and ve-eighths inches deep. The finished stavefor a tub of this size will be approximately fourteen andiifteensixteenths inches long. Tubs of smaller size may, however, bemade from staves produced according to the present invention, suchsmaller tubs being of a capacity to hold five, ten, twenty or thirtypounds of material. Accordingly further reference to specific sizesVwill not be made, it being understood that the method is applicable toany size desired but it Vwill be apparent that if at the cut-off saw apiece of; material is produced which is of insufficient length to make atub of the maximum size, it may be employed for the production of stavesfor a smaller size receptacle. 1 After reducing the Vmaterialjto theproper length at the cut-E saw 10 it is carried by conveyor 11 to anedge jointer machine 12 where the edges of the material are yshaved orplaned square and true and run parallel to the grain;

After having the edges squared, the pieces of material are carried by asuitable conveyor 13 to a set-up bench 14 wh'ere they are assembled intoa blank of approximately square outline and having, where the pieces aredesignedl'for ns'e in making the maximum sizetub, a length of aboutfifteen and a quarter inches and a width of about sixteen and one-halfinches. This assemblage of pieces after being glued up will behereinafter referred to as the blank. Y The set up or assembled piecesfor the blank are then transferred to the glue spreader 15 where theedges of the pieces have glue applied to them and the pieces arereplaced in the previously assembled relation on a blank set up table16. This table is of sufficient size to accommodate eight such blanks intwo rows of four each and these two rows of blanks are moved one behindthe .other into and through a glue dryer. 17 of the electronic typewhere the glue is set.

Preference is had for a glue dryer of the electronic type because of therapidity with which the glue is set to full holding strength, such acondition being obtained in approximately nineteen seconds in anapparatus of this character. Such electronic glue setting devices areof. standard Vconstruction and well known in the trade Vand accordinglyit is not believed that any detailed illustration or description of thesame is required in connection with the setting forth of the presentmethod.

Following the operation of setting the glue, the blanks 1go to the staveshaper which in the flow chart is diagrammatically shown'and designated18. The specific construction and operation of this Shaper will behereinafter more fully set forth. Y

.The blank as `now `set up ready to be operated upon by the' staveshaper appears approximately as shown in Figures 2 and `3 where it isgenerally identified by the reference numeral 19, the individual piecesmaking up the'blank, being designated 19a. The glued up joints "betweenthe pieces 19a are designated 19b.

The blank upon reaching the stave shaper is sawed by means of a'pair ofrotating circular saws constructed and arranged in a novel manner ashereinafter set forth to produce stave pieces. longitudinally taperedand having side edge'orV longitudinal edge bevels, from each of whichtapered and beveled stave pieces, two staves are subsequently producedas hereinafter set forth.

. The circular saws of the stave shaper are mounted at opposite sidesof, a movable carriage guide to rotate on '-axes which converge upwardlyacross the top of the carriage path and the blank is fed to the sawswhile being h eld at anA inclination so that the higher end of the blankVis engaged first by the higher parts of the saws and the lower part ofthe blank passes between the convergent or toed in lower portion of thesaws thereby cutting the stave pieceon a taper and with its longitudinaledges beveled. I The construction and operation of the sawing mechanismis described and claimed in my copending application Serial No. 160,904,filed May 9, 1950, now Patent No. 2,673,585, of March 30, 1954, of whichthe present application is a division. In accordance with the presentmethod, when the initially formed blank is first fed to the saws therewill be produced one, two stave thick piece 20 having the proper beveland taper and a trim piece 21.

In Figure 4 the angular disposition of the saws, designated 22, is showntogether with the trim piece 21 and the first of the tapered stavepieces 20. This'view is taken looking at the low or back edge of theblank and toward the high edge. As will be readily seen in the making ofthis first cut on the blank, ythe left hand saw 22 will form or leavethe right hand edge of the portion of the blank remaining after removingthe piece 20, cut to the correct bevel or taper, such tapered edge beingdesignated a. 1

It will be readily seen by reference to Figure 4, and also to Figure 5,that the toe-in of the saws due to the angle of the axis of rotation orthe supporting mandrils therefor, produces the correct edge bevel ateach side of the blank piece and also the leading or advancing edge ofthe blank, engaging the saws at a higher point or elevation than therear end or trailing edge of the blank, produces the correctlongitudinal taper for the blank piece 20.

The trim piece 21 which is produced from the initially formed blanks,that is the :blanks formed originally from the straight pieces 19a, isnot discarded or wasted. When a number `of blanks have been cut in themanner thus far described so that an equal number of these trim piecesare produced, such trim pieces are sent back to the table 16 where theeight blanks are set up as previously described. Here these trim piecesare edge glued to the squares and, as will be readily seen, the blanksthereafter coming from the electronic edge gluer to the stave Shaperwill have one edge correctly edge beveled and tapered. Such a blank isshown in plan in Figure 6 and in edge elevation in Figure 7. In thesefigures the properly beveled and tapered edge face of the applied trimpiece is designated b.

Consideration will now be given to using blanks set up as shown inFigures 6 and 7, having the trim piece 21 from a preceding blank forminga part thereof and edge glued to one side as indicated at 21a, wherebysuch blank, here generally designated 19e` goes Vto the stave shaperwith one edge properly beveled and tapered. Two ways may now be employedfor cutting the stave pieces from the blanks 19e by means of theinclined saws and by feeding the blank to the saws in the mannerpreviously set forth. Y

The first of these two ways of cutting the blank as shown in Fig. 12would be to feed the blank to the saws, after properly setting the blankin position, with the advancing edge higher than the trailing edge asbefore stated, so that the already formed beveled and tapered edge bwill move across the inclined face of the right hand saw and the lefthand saw will cut longitudinally through the blank. In this procedurethe right hand saw performs no work and a single stave piece r20 isproduced. The remaining blank piece from which the single stave piecehas been cut, is then turned upside down end for end and again' fedforwardly to be operated upon by the single left hand saw, the righthand saw again following the right hand inclined or beveled edge face ofthe work. In other words each time one stave piece is sawed from theblank, the blank Vis reversed or turned over end for end as statedbefore the next stave piece is cut ot, in,

stave pieces are produced or cut from the blank at ati'me, illustratedin Figure 5. Withthis manner of proceeding it will also be apparent thatthe need for reversingy or turning the blank is avoided, the blankmerely being run through again in the same manner so as to cut two morestave pieces therefrom.

The stave piece 20 produced in either of the two ways above set forth,is shown in perspective in Figure 8 and from this tapered piece twocompleted or finished. staves are eventually produced as hereinafter setforth.

After cutting from each blank as many stave pieces as possible, orfour'pieces, a remaining strip is obtained which corresponds to theoriginal' trim strip and which maybe sent back to the blank assembly orset up table tobe added to the blanks in ther Same manner as the trimstrip 21, this last named or remaining strip being designated 23. Thusit will be seen that the pieces cut from the blanks in the formation ofthe stave pieces, namely the trim piece 21 and the remaining or tailpiece 23, are not wasted but go into themaking of additional blanks andgive to such additionalblanks analready beveled and properly taperededge form which becomes one longitudinal side or edge of a subsequentlyproduced stave piece.

It will be noted that inV carrying out the'methodto the point described,after the individual pieces 19a have been cut to the proper length thereis nothing removed from the blank which is discarded or wasted, exceptVthe sawdust, and the stave pieces 20 while properly-tapered and beveled,have their inner and outer faces at and parallel.

From the stave Shaper, the stave pieces 20, each of which is of athickness to have two staves produced'from it, proceed to what is termedthe equalizer, which is designated 24, where the staves are fedhorizontally edgewise to a pair ofy spaced parallel saws which cut thestave piece to the proper length.

From the equalizer the properly lengthened stave pieces move to bandsawY machines 25 which forms the subject matter ofl my Patent No.2,682,285, where the stave is fed or moved'in anV arcuate path to thevertical band: saw, while being maintained vertically on its end. Thestave piece is thus cut or divided longitudinally into the pieces, alongan arcuate path from one longitudinal edge to the other, such cut lineor line of division being shown in Figure 9 and designated 26. There arethus produced two pieces of the form shown in Figure 10, designated 20aand 20h. As shown the piece 20a has one Side face transversely convex asindicated at 20e while the other piece has one side face transverselyconcave as indicated at 20d. Each of these pieces 20a and 2Gbconstitutes an incomplete stave.

Completion of the staves is eected by feeding the pieces throughsuitable planers described and claimed in my Patent No. 2,682,285, theplaner station being designated 27 in the ow chart and representing thelast stage of the method. At the planer 27 there is provided a convexplaner unit 2S which gives the convex transverse curvature to thepreviously hat side of the incompleted stave 20b and a concave planerwhich gives a transversely concave face to the previously hat side ofthe incomplete stave 20a.

The two planer units 28 and 29 may form a part of a single machine byhaving the units mounted upon a single shaft 30 which operates inconjunction with a parallel shaft 31 which carries convex and concavefeed rollers 28a and 29a respectively.

The planers are here more or less conventionally shown and it will beunderstood that any suitable supporting means may be provided for therotary shafts 30 and 31 and also suitable means for rotating theseshafts at the desired speed as shown in my Patent No. 2,682,285 abovereferred to.

As previously stated the sawing mechanism by which the two stave pieces20 are cut from the blank and given the proper taper and bevel isillustrated in detail and ,6 claimed in my Patent No. 2,673,585. In thisconhetion, where the stave pieceis. formed for thev production of stavesdesigned to be. used in a tubof the larger size the piece is givenapproximately a one andi a half degree taper on each. side from end toend andl an edge angle of 15 front to back as indicated in Figures 8'and 9. In the sawing mechanism there are provided twospaced arbor frames55 each of which includes in its structure the 'two spaced, axiallyaligned bearings 56 which support the saw arbor 57. Each of these arborscarries the V-belt pulley 58 which is in driving connection by means ofV-belts 59 with a suitable driver pulley, not shown.

As shownl the arbors 57 have their axes upwardly con vergent andintersect in a vertical plane extending longitudinally'of the center ofthe support on whichthe work piece is held. The inner ends of thesearbors, however, terminatev short of this central planev and eachcarries upon such end the circular saw 22 hereinbefore referred to.While these saws 22 are in downwardlyV convergent planes the bottomedges of the saws are spaced quitefar apart while the top parts of thesaws are, of course,- a considerably greaterdistance 'apart' for thepassage therebetween of the. support for the work piece.

As previously set forth the stave piece 20 will' have produced from ittwo complete staves of proper transverse curvature, taper andlongitudinal edge bevel for finali assembly into a tub or pail. Aspreviously set forth the trim-.piece 21 which has one edge properlybeveled andi the other edge straight or square with the top and bottomlsurfaces, goes back to the blank assembly table and 'forms the outerside pieceof'another blank, as illustrated in Figures 6 and'7 so thatwhen this blank comes to the stave Shaper machine it will have onesidealready cut` to the proper taper and bevel: This is another importantfeature of the present invention in providing'for economy in therawmateriall since initial trim pieces are not discarded but go into themaking of subsequent blanks and, because of the factY that suchsubsequent blanks come to theV stave Shaper machine with an edge alreadycut and beveled, a savingin timeis effected iniproducing the desiredstave pieces from such blank.

After the stave pieces have been produced in the manner stated they arecut to length by a suitable mechanism.

Following the squaring of the ends of the stave pieces, the pieces aredivided along the arcuate line 26 as shown in Figure 9 by means of thespecial band saw mechanism forrniny the subject matter of my Patent No.2,682,285 previously referred, producing the two incomplete staves 26aand 20h, shown in Figure lO.

The procedure followed after the formation of the two incomplete stavesby the operation of the band saw has been previously set forth, namely,the running of the incomplete staves through a planer such as thatconventionally illustrated in Figure ll and which comprises a cutterhead carrying convex blades in cooperation with a concave feed rollerand a second cutter head on the same shaft as the first and carryingconcave cutter blades which cooperate with a convex feed roller. rhisfinal operation cuts away the at faces of the two incomplete staves soas to bring the completed staves to transverse arcuate form and to onethickness, in which condition they are then ready to be assembled toform the completed tub or pail.

From the foregoing it will be readily apparent that there is provided bythe present invention a new and novel method of forming tub and pailstaves by which a great economy can be effected in the manufacture ofsuch articles by the use of material which has heretofore been wasted.Also according to the present method the reclaimed scrap material isassembled and sawed in a novel manner whereby considerable economy iseffected through the integration into the set up blanks of initial trimpieces which become a part of the finished stave piece and the resultingstaves produced therefrom.

HIclaim;

1. The improved method of producing tub and pail staves which comprisesthe steps of preparing a blank having a length greater than a finishedstave and a width greater than a tinished stave, then sawing the blanklengthwise along twok convergent lines 4and .in downwardly convergentplanes; to produce a stave piece of desired longitudinal taper andlongitudinal edge bevel,Y cutting the stave piece to length, thenYdividing such Vstave piece lengthwise on an arcuate line lying betweenthe sidefaces of the piece and extending from and through one bevelededge to the other toproduce twoY incomplete staves each having onetransverselyr curved nished face, and iinally planing the other face ofsuch incomplete stave to a transverse curvature substantiallyparalleling the said one finished face thereof.

2. The improved method of producing tub and pail staves from a pluralityof wood pieces which may be individually of insuicient width for suchuse, which method comprises edge squaring a number of such pieces havinga length greater than the desired finished stave, assembling and edgegluing such pieces together to form a at blank havinga width greaterthan the combined widths of a number of iinished staves, then sawing theblank lengthwise along two convergent lines and in down- -wardlyconvergent planes to produce a stave piece of desired longitudinal taperand longitudinal edge bevel,

repeating such sawing operation to produce the maximum number of piecesfrom the blank, cutting said pieces to the desired length of iinishedstaves, cutting each piece lengthwise along a curved transverse line toprovide two partially completed staves each having one side surface atand the other side surface transversely curved and inally shaping saidflat surfaces to the desired curvature to provide complete staves.

3. The method as set forth in claim 2 which includes the step of addingto subsequently made up blanks a trim strip resulting from the cuttingof the iirst stave piece, said trip strip having a beveled edge andbeing assembled in said subsequently made up blank to form onevlongitudinal border with its beveled edge positioned to provide a readyformed beveled edge of the trst talperedstave piece cut from the blank.

4. In the manufacture of tub and pail stavesthe novel method forutilizingv mill scrap Wood `pieces having a length greater than thestaves but of widths insutiicient for such useindividually, said methodcomprising assembling a number of such pieces in edge to edge relation,gluing the assembled pieces together to form a at blank having a widthgreater than the combined widths of a number of staves, then sawing theblank in one operation along twoV longitudinally convergent lines and indownwardly convergent planes to produce a longitudinal trim strip and astave piece, the stave piece having the longitudinal taper andlongitudinal edge bevel of a stave and said strip having onelongitudinaledge of the same bevel as a stave, employing said trim stripas a border piece in the making up of a subsequent blank with thebeveled edge of the strip disposed outwardly and sawing said subsequentblank longitudinally along one line convergent with said strip edge andin a plane convergent with the plane of the bevel of such edge toproduce a stave piece from which a completed stave may be produced. Y

5. The method as set forth in claim 4, with the additional steps ofdividing the stave piece through its length on Van arcuate line lyingbetween the side faces of the piece and passing through the bevelededges thereof Yto produce two incomplete staves each having one finishedtransversely curved face, and then planing the other face of each staveto a transverse curvature paralleling the said one face. Y

References Citedin the le ofthis patent UNITED STATES PATENTS

